Doctors in China have reattached a man's severed hand after keeping it alive for a month by attaching it to his leg.

The 25-year-old, identified by his nickname Xiao Wei, had his right hand sawn off by a drilling machine at work last month in Changde, in the central province of Hunan, the Xiaoxiang Morning Herald said on Tuesday.

The damage was too severe to re-attach the hand immediately, so surgeons grafted it onto his lower leg, just above his Achilles tendon, to keep it alive while the healing process began.

Severed limbs can be saved if their blood supply is restored within several hours of their amputation, depending on the circumstances.

Earlier this month, doctors removed the hand and successfully reattached it to Xiao Wei's arm in a nine-hour operation.

He will have to go through several further operations and rehabilitation therapy to restore the limb's function, the report added.

"It's just like building a house," the paper quoted Tang Juyu, Xiao Wei's primary doctor, as saying.

"Currently the main body is established. There will have to be interior decorations in the future."